import java.util.Scanner;

/**
 * @Question 刷题统计
 * @Date 2023/3/8 9:19
 * @Solution
 */
public class 刷题统计 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long a=scanner.nextInt();
        long b=scanner.nextInt();
        long n=scanner.nextInt();
        long[] d={a,a*2,a*3,a*4,a*5,a*5+b};
        int count=0;
        long total=a*5+b*2;
        count+=(n/total)*7;
        n%=total;
        if(n==0) {
            System.out.println(count);
            return;
        }
        for(int i=0;i<d.length;i++) {
            if(n<=d[i]) {
                System.out.println(count+i+1);
                return;
            }
        }
    }
}
